Pokemon Go is a monster mobile hit

Police in Missouri put out a warning that was both terrifying and bizarre: Armed robbers were believed to be targeting people hunting for Pokemon.

You read that right. Pokemon. The little monsters.

Police said the victims were playing Pokemon Go - a new smartphone app that encourages gamers to search local areas to find Pokemon in the "real world".

Certain locations offer bonuses and higher chances of catching rare species and that's where officers said criminals had been lying in wait.

"It is believed these suspects targeted their victims through the Pokemon Go smartphone application," the post on the force's Facebook page read.

"Apparently they were using the app to locate people standing around in the middle of a parking lot or whatever other location they were in."

O'Fallon Missouri Police Department published mugshots of three suspects allegedly involved in the Pokemon-related armed robbery

The incident was just one of several odd goings-on in the first weekend of Pokemon Go's release - a title that achieved such rapid popularity it had to be briefly shut down while servers were upgraded to handle demand.

Read more

What is Pokemon Go?

Nintendo's shares soar on Pokemon Go's success

Pokemon Go player finds dead body

Pokemon Go's UK launch is "paused"

Firm sacks worker for Pokemon rant

The app's innovation is its use of augmented reality (AR). The Pokemon are placed within real-life views captured by the phones' cameras.

When I fired up my app for the first time, a little Charmander was lurking near my TV cabinet.

Charmander is one of more than a hundred characters available in the app

Within moments, I had my shoes on and was out of the door to find more - I needed to get to a nearby Pokestop, a location where you gather supplies.

It turns out the fairly inconspicuous corner near my flat is something of a Pokemon hotspot thanks to a little landmark - a mural above eye level - that I hadn't even noticed before.

Great, I thought - that'll be handy, having a Pokestop so near my house. And then it hit me - I'm 30 next year.

'Bigger than Tinder'

The Pokemon franchise has always been huge business, but the game's prior success may pale in comparison to what's ahead for the app.

So far, its launched in the US, Australia and New Zealand. Europe is up next. Oh, and Japan. I think it'll go down well there, somehow.

Pokemon Go is not yet available via the UK's app stores

Some gamers are using workarounds to avoid the wait - such as signing in with a US iTunes account on a UK phone.

Its success isn't just anecdotal. Pokemon Go has already been installed on a phenomenal 5.16% of all Android smartphones in the US, according to SimilarWeb, an app analytics firm.

For context, that's more installs than dating app Tinder. Almost double, in fact.

SimilarWeb estimates that by the end of the week on Android, Pokemon Go will have more active users than Twitter. Twitter!

Right now, the average time players are spending on the app is about 43 minutes a day. More than WhatsApp, Instagram, Snapchat and Facebook Messenger. That will presumably dwindle away a little, but wow - what a start.

It's terrific news for Nintendo. The beleaguered Japanese gaming giant has a 33% stake in the Pokemon company and has also created a small wearable accessory that buzzes if the monsters are nearby.

The Pokemon Go Plus vibrates on its owner's wrist, meaning they are less reliant on checking their smartphone's screen

Since Pokemon Go's release, Nintendo's share price has soared - up by almost 25% in Monday's trade on the Tokyo Stock Exchange.

Until now, the firm had all but snubbed smartphone-gaming. But this title could come to define the activity in the way its Game Boy did for handheld consoles all those years ago.

Moral panic

But like every new craze, particularly one that is likely to obsess children, we're now entering a period where any story with a Pokemon Go angle instantly grabs attention.

First up - there are privacy concerns.

The app needs lots of permissions - location data, camera and more. Almost overnight, its developer Niantic has found itself in possession of an enormous amount of data about specific people. People are putting pressure on it to clarify what it intends to do with that information.

The original Pokemon games were released in Japan 20 years ago for the Game Boy

Parents might also feel worried about their kids wandering, zombie-like, into areas of towns they wouldn't normally go.

Furthermore, the in-app purchases are enough to make your eyes pop out: $99.99 (£77.73) gets 14,500 Pokecoins to buy things in-game - you can, of course, purchase smaller amounts.

Alongside Missouri's police warning, we've also seen darker scenes in Wyoming, where a Pokemon Go trainer reportedly stumbled across a very real dead body.

And authorities in Washington State are urging players not to combine the activity with driving.

The authorities are urging the public to play safely

Though that did give Keith Green, from South Carolina, an idea.

"For the low price of $10 per hour," he offered, "you can have me drive you around on a Pokemon Safari.

"This way you can focus 100% of your attention on catching those little [monsters] while not posing a danger to other people on the road! Just say the word 'Charizard' and I'll slam on the brakes."

He told me no-one had taken him up on the offer. Yet.

Follow Dave Lee on Twitter @DaveLeeBBC and on Facebook.